1. Field
Example embodiments of the following disclosure relate to an apparatus and method for decoding audio data, and more particularly, to an apparatus and method that performs block data unpacking, through preferring a channel order to a block order from a bitstream, and that performs dithering through preferring a block order to a channel order.
2. Description of the Related Art
An audio bitstream transferred via digital broadcasting, such as a Blu-ray disc or a high-definition television (HDTV) may be generated through compressing audio data in a digital audio format. Improvements relating to a quality of audio data have led to the further development of the digital audio format.
In particular, as a sound quality is enhanced when compared to a sound quality having the same bit rate, a number of channels of digital audio data may be extended. As the number of channels is extended, a digital audio codec is transformed into a form of providing additional functions in order to process the digital audio data with an enhanced sound quality. As used herein, a digital audio codec for processing digital audio data of a previously known number of channels, for example, a 5.1 channel, refers to a general audio codec. Further, a digital audio codec for processing digital audio data through an extended number of channels, for example, a 10.1 channel and a 13.1 channel, refers to an enhanced audio codec.
For example, when the general audio code includes Dolby Digital, the enhanced audio codec may include Dolby Digital Plus. Dolby Digital Plus may perform a more enhanced additional function than Dolby Digital, such as, transient pre-noise processing, enhanced channel coupling, adaptive hybrid transform processing, and spectral extension.
A block allocated to a horizontal axis and a channel allocated to a vertical axis may exist in a frame of a bitstream to be processed by the enhanced audio codec. The enhanced audio codec may unpack a frequency value of the digital audio data from the bitstream. More particularly, the enhanced audio codec may perform bitstream searching that searches for a location at which a predetermined block commences from the bitstream. In a subsequent step, the enhanced audio codec may perform block data unpacking to unpack block information, such as an exponent and a mantissa, based on the location of the block extracted as a result of the bitstream searching.
In this instance, the enhanced audio codec may perform the bitstream searching and the block data unpacking sequentially via a plurality of modules, respectively. Although actual results to be extracted from the bitstream searching and the block data unpacking may differ, overlapping operations may exist. Accordingly, a decoding complexity for processing the bitstream via the enhanced audio codec may be reduced through integrating the overlapping operations.
Maintaining a resulting value to be consistent may be required, irrespective of a change in an operation of the enhanced audio codec, despite a change in a detailed operation of the enhanced audio codec in order to reduce the decoding complexity.
Accordingly, an improved apparatus and method for decoding audio is desired.